1. Field of the Invention
The present invention relates to the Internet and the Public Switched Telephone Network (PSTN); and more particularly to the integration of the Internet with the PSTN in a manner such that systems, services, and devices on either can communicate with systems, services, and devices on the other, so that the full benefit and unique characteristics of either network are available to these communications.
2. Description of the Prior Art
The Internet and the PSTN constitute discrete, independent networks from an architectural and operational perspective. Much is written about both networks, especially in terms of their architecture and operation. Consequently, the specification provided herein does not reconstruct that information other than providing general background information. The term “Internet” is commonly understood and used throughout the specification and claims in a conventional way. The Internet, in general, is an assemblage of interconnected routers that provide data transport services for server computers and user devices—typically PCs. The interconnection between routers is provided by private line data circuits, the main lines of which constitutes the Internet “backbone”. Internet Service Providers (ISPs) provide access to the Internet via dial up telephone lines with modems, and via dedicated arrangements such as T-1 circuits, cable modems on cable-TV systems, and DSL (Digital Subscriber Line) service.
The Internet is designed according to the Internet Protocol (IP), which provides detailed specifications for the construction, addressing, and routing of data packets (occasionally referred to as “messages” in this document). (The term “Internet Protocol” also is used loosely to refer to dozens of related protocols that are used in the Internet.) IP addresses are expressed as a series of digits separated by “dots” (periods), in the form XXX.XXX.XXX.XXX where XXX can be a number from 0 to 255. IP addresses provide a similar function on the Internet as telephone numbers provide on the PSTN. A communication with an Internet device can be established by sending a message addressed to the IP address of that device. Every device capable of communicating on the Internet has an IP address assigned to it, either permanently, or dynamically as needed. IP addresses in some environments are replaced with a proxy address; for purposes of this document, the term “IP address” shall refer to an actual IP address, or a proxy or other identifier translatable into an actual IP address. In some of these arrangements, the IP address may be indirectly associated with the device. For example, in a wireless handset arrangement, the provider's complex might provide Internet connections for wireless handsets on a proxy basis wherein the complex keeps track of IP number assignments used for each handset, but communicates with each handset based on a serial number or other unique identifying scheme. The same goal is accomplished, i.e. an Internet capable handset gets its own IP address, but with one level of indirection. In other arrangements proxies or agents act on behalf of a client system and substitute the proxy's IP addresses for the addresses of the client devices—in these arrangements the combination of the proxy address and the original client system address resolve to provide a unique IP address for each client system. Internet data packets contain the IP address of both the sending system and receiving system (the source and destination, respectively). Since IP messages always contain the IP addresses of both the sending and destination device, when a device receives an Internet message from a sending device, it will then possess the IP address of the sender and can send messages in reply. The two devices can then engage in a communication across the Internet since each has the IP address of the other.
Routers have internal tables that provide routing instructions, which relate IP addresses to the available data circuits and access lines. A router functions by reading the destination address in a data packet, and then forwarding the data packet on one of its data circuits or access lines according to the rules of the routing tables. A data packet gets forwarded from one router to another, pinballing its way across the Internet until it reaches a router that is connected to the destination system.
The term “Public Switched Telephone Network”, or PSTN, as used herein means the national and international telephone network, actuated when a user dials a telephone number associated with any other phone, causes it to ring, and if answered, is enabled to carry on a voice communication (or, more properly, a “voice grade” communication) with the person (or system) at the remote location. Just as the Internet is comprised of an aggregation of interconnected routers, the PSTN is comprised of an aggregation of interconnected local and long distance telephone switching systems. The local switching systems, referred to as telephone company (telco) central offices (CO), provide telephone subscriber services in a geographic area.
As used herein, the term “telephone central office switching system” refers generically to a class of systems, typically owned by the operating telephone company in any given area, which provide “local” telephony services to telephone subscribers in that area. Generally, the operating telephone company provides the “local loop” cabling and wiring from its central office to the physical location of each of its subscribers (a “telephone circuit”, or a “line”). A telephone central office might house several switching systems of this class, each serving up to 100,000 subscribers or more. The central office represents the hub of a wheel having thousands of spokes, each spoke being a physical pair of wires providing telephone service to a subscriber in that area. Subscribers in any given area are provided service by the central office situated in the center of the area. Outside that area the wires home to other similarly situated central offices. The telephone company connects the telephone circuit of a subscriber to an access connection on the switching system, and assigns a telephone number to that circuit. In operation, the switching system (or just “switch”) provides battery voltage on the phone line, sends dial tone to the subscriber line when the subscriber's phone goes off hook, receives the dialed digits, and then routes the call according to its internal instructions based on the called number.
Common manufactured switching systems of this class include the Lucent Technologies 5ESS, and the Nortel DMS100. All telephone central office-switching systems around the world are interconnected by “trunk” circuits that carry voice or voice grade telephone calls between systems, and most (if not all) such systems are also interconnected by a messaging network referred to as CCS/SS7 (Common Channel Signaling/Signaling System 7), or just SS7. Long distance calls to telephones outside of the area served by the local telephone company are typically routed to a long distance carrier, such as AT&T, MCI, or Sprint in the USA. The telephone central office switches connect via trunking and messaging circuits to a class of switching system referred to as a “toll switch”, such as the Lucent Technologies 4ESS, operated by a long distance carrier. Toll switches normally do not provide local telephone services.
In the current state of the art there are two inter-related messaging systems utilized within the PSTN. These are: (i) SS7; and (ii) ISDN (Integrated Services Digital Network), which incorporates a messaging system as an element of a broader product and service architecture. The SS7 messaging system extends through the major elements and systems of the PSTN, connecting virtually all of the local and long distance central offices, and carries call management (or call control) messages relating to call setup and disconnection and similar call management functions. Whereas the SS7 messaging system is oriented toward providing messaging communications among and between the PSTN switching systems, the ISDN messaging system is oriented toward extending the PSTN messaging system to the end devices such as telephones and office telephone systems. Rather than going off hook and drawing dial tone from the local central office switching system to initiate a call, as analog phones do, an ISDN phone sends a packetized digital call setup message to the switching system to initiate a call. Both the ISDN messaging system and the SS7 messaging system are based on the X.25/X.75 communications protocols. ISDN messages are carried on the SS7 messaging network. Disadvantageously, neither the SS7 nor the ISDN messaging systems carry any messages related to creating an Internet communication by one device dialing the telephone number of another.
The ISDN and SS7 messaging systems are call setup and call management (or call control) systems which carry a spectrum of messages, message responses, message acknowledgements, and the like, such as are necessary to conduct telecommunications. A full listing of all the message types that might be employed in a robust telecommunications environment has not been attempted herein, since that depth of information is not necessary to convey the essential elements of this invention. A brief listing of those message types include: (i) call setup request messages which convey dialing and associated information; (ii) busy signal messages telling the calling device to deliver a busy signal to the user; (iii) audible ring back messages telling the calling device to deliver “pacifier” ringing to the user; (iv) call request acceptance or rejection messages (v) call connect messages; (vi) call disconnect messages; (vii) switchhook flash messages; (viii) call transfer request messages; (ix) call conference messages; (x) call waiting messages; (xi) Caller-ID and Call Waiting-ID messages; and (xii) call forwarding messages to redirect a call to another device. In addition to these messages, a variety of other messages would be employed to indicate information like “network busy”, “invalid telephone number dialed”, and the like.
Conventional communication vehicles comprise computers and telephones. Computers typically have telephone lines attached to them, and telephones oftentimes have computers attached to them; but there is no true integration that enables the blending of the Internet and the PSTN. The level of integration that is presently attained permits a computer to use a phone line to dial into the Internet. Once on the Internet, the computer can access another computer by entering its Internet Protocol (IP) address into application software such as a browser.
The full benefits of integrated communications are not presently attained with conventional Internet and telecommunications environments. There exists a class of devices, such as those for Voice over IP, DSL, cable TV, fixed wireless, Internet capable wireless cellular, and similar distribution systems, which provide Internet and telephony services to client devices, such as phones and PCs, by providing an interface to the telephone company central office switching system. The environments of Voice over IP service and DSL service are illustrative of current telephony environments in relationship to the switching system that serves them. Such environments are addressed herein initially by examining the current state of the art of these systems.
In one aspect, the systems described herein relate to Voice over IP service. The term IP refers to the “Internet Protocol”, the basic protocol of the Internet, while the term Voice over IP refers to sending digitized voice across the Internet using the IP protocol. Several companies provide discount rate phone calls using “Voice over IP” (VoIP) technology, wherein a long distance call of a client, typically a Personal Computer (PC) user, is carried over the Internet to a VoIP interface device in the vicinity of the called party. Such VoIP technology avoids the charges associated with placing a long distance call with a traditional long distance carrier. The interface device dials a local call on the PSTN to complete the connection for the VoIP client. Hence, the call travels partially over the Internet and partially over the PSTN. A VoIP software application at the client device digitizes the user's voice and sends that as data messages across the Internet to the VoIP interface device. The VoIP interface device in turn converts the data messages to analog signals that are output onto the analog phone line. In the reverse direction, the VoIP interface device receives analog signals from the dialed phone and converts those analog signals to digital messages, which it sends across the Internet to the VoIP client. The VoIP software at the client converts those digital messages to analog signals, which are output to the user via speakers.
In another aspect, the systems described herein relate to DSL service. An Internet access technology currently deployed is referred to as DSL service. (The original acronym was ADSL, for Asynchronous Digital Subscriber Line.) Although there are some variations on the technology (now generically referred to as “xDSL”), it essentially involves an analog telephone line supplemented by a high frequency carrier signal superimposed on the telephone line by a pair of modems—one at the subscriber location, and one at the telephone company central office. The DSL carrier signal can carry high-speed data concurrently over the same phone line without interfering with the analog phone service. Other than being carried by the same physical wires, the phone line has no relationship to the DSL Internet service.
In another instance, the matter to be discussed relates to virtual phone service provided via cable-TV. Cable-TV service has been used to provide high-speed Internet access—the popular “cable modem” service. In addition, there are a number of current activities related to delivering alternative provider telephone service via the cable-TV distribution system. Similar to the Internet access service arrangement, the telephony service arrangement utilizes a “cable modem” to transmit and receive voice grade telephone calls. Other than being carried by the same physical cable, telephone service provided by cable-TV has no relationship to the cable modem Internet service.
A related matter is that of virtual phone service provided by the so-called fixed wireless arrangement, currently undergoing field trials in some areas, and by the newly introduced cellular telephone service with Internet access. Although these are substantially different services from a user perspective, the wireless infrastructure is much the same.
In each of these technologies, even though they provide both Internet and PSTN connectivity, the Internet aspect is separated from the telephony aspect. Furthermore, none of these technologies enables one device to create an Internet communication with another device simply by dialing its telephone number.
In FIG. 1 there is shown a schematic illustration of a conventional Internet and telephony environment, including the Internet, a telephone central office with a switching system, and VoIP and DSL interface devices.
Referring to FIG. 1 of the drawings, Personal Computers (PCs) or similar devices 33, labeled “C” and “D” reside on a Local Area Network (LAN) 35 connected to the Internet 10 via an access line 28, commonly a T-1 type of circuit. Telephones 20 are connected to the telephone company (telco) switching system 14 by telephone lines 18. Switching system 14 has voice trunking 36 to other switching systems, along with SS7 messaging circuit 38 to convey conventional call setup and similar operational information between switching systems. Switching system 14 resides in a telco Central Office facility (C.O.) 12, which also houses a Voice over IP (VoIP) interface device 24 having a similar access line 28 and multiple telephone lines 18. Although the VoIP interface device, and other interface devices discussed herein typically are co-located in the telco central office, it could be located elsewhere with the appropriate interconnecting circuits trunked in via any of a number of types of multiplexed data circuits. Operationally, multiple, concurrent voice sessions are carried digitally over access connection 28 (multiplexed), and are demultiplexed or distributed to individual telephone lines 18 by the interface device 24. The hatched portion 26 of interface device 24 is a router function, which may be built into the interface device as shown, or may exist as a stand-alone device.
The purpose of the VoIP interface device is to allow Internet users such as C and D to make voice telephone calls. The Voice over IP carrier provides each of its users with a software application (not shown) that enables the computer user to enter a number to be dialed. By way of example, one of the computer users 33 labeled “C” dials the telephone number of a telephone 20 labeled “E” by using the VoIP software application. That software application, perhaps operating in conjunction with other systems of the VoIP carrier, creates a logical connection to a remote VoIP interface device such as 24 by sending a call setup request message to it over the Internet. The call setup request message contains the called telephone number (TN) as well as the calling device's IP address. The VoIP interface device 24 then takes a telephone line 18 “off hook”, and dials the telephone number of telephone 20 labeled “E” on behalf of computer user C. Switching system 14, upon receiving the dialed digits, connects the telephone line 18 from the VoIP interface device to the telephone line 18 serving telephone C. The VoIP device then acts as a conduit for the resulting voice grade connection between the two devices. Switching system 14 is unaware that the call originated from a PC, and does not know the PC's IP address.
In a second example, computer user C dials the phone number of computer 33 labeled “A”. As before, a call setup message is sent from A to the VoIP interface device, resulting this time in switching system 14 connecting the telephone line 18 from the VoIP interface device to the telephone line 18 serving telephone associated with computer A. There is no provision for this connection to connect to computer A, only to the analog phone associated with A. Moreover, in each of the preceding examples, no means is provided for the calling and called device to create an Internet communication between themselves when one of the devices is called by dialing a telephone number.
Next described is the DSL operation for the environment just described. With continued reference to FIG. 1 of the drawings, the Internet 10 is associated with the telephone central office as 12 containing the telephone switching system 14 through a DSL interface device 22 incorporating DSL modem circuit cards 40. Analog telephone lines 18 connect from the telephone switching system 14 to the DSL modems 40. The DSL interface device has an access line 28 to the Internet. Emanating from the DSL interface device 22 are telephone lines 30 carrying the composite signal of analog plus carrier wave to the client devices. The carrier wave portion of the telephone lines 30 terminates in DSL subscriber modems 29, which split off the analog phone line 18 terminating on a phone 20 separately from a high speed data connection 31 to the user computer 33. The high-speed data connection 31 is typically an Ethernet connection. DSL service as currently provisioned creates an Ethernet connection for the user computer and an analog voice connection for the user phone.
The purpose of the DSL interface device is to allow Internet users such as A and B high speed access to the Internet 10, while still allowing the respective telephones 20 of A and B to function as analog phones. By way of example, computer users 33 can access resources on the Internet 10 via the DSL interface device 22, the incorporated router function 26, and Internet access line 28. The users of A and B can use the respective telephones to dial telephone calls, which activity is passed transparently through the DSL interface device 22 to switching system 14, whereupon it is handled by the switching system as an ordinary telephone call. No means are provided for the calling and called devices to create an Internet communication between themselves when one of the devices is called by dialing a telephone number.
In the environment just described, switching system 14, VoIP interface device 24, DSL interface device 22, or any other similar interface devices, exist as separate, nonintegrated systems, and as such are not capable of exploiting the full advantages of integrating the Internet with the PSTN.
There presently exist designs of voice communications systems such as office PBX's (Private Branch Exchanges) which operate in “pure packet” mode. Prior designs of communications switching systems operate in “channelized” mode, in which resources are dedicated to a voice communication for the duration of a call, regardless of whether you are singing or holding your breath. In packet switching, resources are only consumed when there is actual (voice) data to transmit. Packet switching designs for data have been available for years, and in fact are central to the Internet; but the packet switching concept has not generally been applied to voice communications because the remaining entirety of the telecommunications world is channelized. New “pure packet” PBX designs, however, anticipate a change, especially in regard to transmitting voice traffic over the Internet. For years, most voice calls have originated as analog, and have been digitized at the telco central office, only to return to analog to be delivered to the destination phone. Pure packet PBX's also digitize the voice, but assemble groups of digitized elements and wrap those groups in an IP packet. The packets are then routed internally in the switch in the same manner that Internet routers function, with the advantage that the packet is compatible with all Internet devices, and hence the exact same packet can be sent out a data communications link across the Internet. However, even though there are advantages and promises to “pure packet” designs for switching systems, they have limited application to conventional Telco central office switching systems due to the channelized nature of the PSTN.
Accordingly, to further promote the integration of the Internet with the PSTN there remains a need in the art for a method and means to integrate the functions provided by these systems and devices, and to provide an environment for the effective implementation of pure packet telco switching systems.